1. User login (Admin, Broker or Client)
2. Stock Trading. Clients can view shares prices and submit orders to brokers for
buying or selling
3. Brokers can issue the order; manage client’s finance and billings and offer
recommendations based on current prices and client history.
4. Stocks Activity Reports (By day, month or year)
please help me in this basic project and diagram
You haven't asked for help, you asked for a full solution.
If you want help, then you first need to do as much as possible by yourself, up to the point where you don't know how to proceed. Then tell us why you can't proceed and what, precisely, it is that you don't understand or don't know how to solve.
There's no point for us to provide a full fledged answer if we don't know what you already know - we might just be wasting our time telling you what you already know!
You may be unsure on how to start, maybe you believe if your design isn't perfect right from the start then you will ultimately fail. But that is not how software development works: software development never starts with a perfect design! Instead you start with what you think works best, and go on until you realize that you can't go on, or some detalis of your design are impractical. Then, based on what you've just learned, you correct your design. If all else fails, start new from scratch.
GOTOs are a bit like wire coat hangers: they tend to breed in the darkness, such that where there once were few, eventually there are many, and the program's architecture collapses beneath them. (Fran Poretto)
To understand the SP's functionality, we recently took one of the device vendors SP's DLL for accessing their device and we were able to successfully communicate with their device using our windows application(Eclipse MINGW based).
I googled the error message you mention and could not find it in the Windows API. It doesn't look like a Windows error message. I'm afraid the maker of the device might be the only one who could help you with this problem.
Perhaps this is a call stack corruption caused by removing the WINAPI definition. WINAPI simply means __stdcall which is the calling convention used by the Windows API.
The difficult we do right away...
...the impossible takes slightly longer.